A pleat is pressed memory — and like any memory, it fades fastest when handled carelessly. Three habits keep it sharp.
First: hang from the waistband, never folded over a bar. The weight of the skirt is what re-draws the pleat every night.
Second: steam, don’t iron. An iron flattens the fold’s edge; steam relaxes the cloth around it and lets the pleat re-set itself.
Third: rest it. A pleated piece worn two days running never gets to recover. Alternate, and the pleats will outlast the occasion you bought them for.